1. Field of the Invention
The present invention relates generally to a vehicle cabin heater and, more particularly, to a rapid warm-up spot heater for a motor vehicle.
2. Description of the Prior Art
Vehicle cabin heaters utilize engine cooling water as a source of heat for heating a vehicle cabin. However, in areas where ambient air temperature is often below -10.degree. C., such heaters encounter problems in that considerable time is required to raise the temperature of engine cooling water to a sufficient level after starting the engine, requiring vehicle passengers to do without effective heating for about 15 to 20 minutes until the heater becomes normally operative.
To solve this problem, electric spot heaters have been proposed. This type of heater comprises a heater element of electrically resistant material and an electric fan and functions to heat air by electrically energizing the heater element to supply warmed air to a desired area, such as an area surrounding the driver's feet, by the action of the electric fan. With this arrangement, the vehicle passenger is given a feeling of heating.
In this type of conventional spot heater, however, a large amount of electric power is consumed due to its inherent construction. In cold areas where spot heaters are required, a large capacity battery is necessary considering the power drop of it, and the electric supply to the battery by an engine-driven generator is made by increasing the engine output to a degree greater than that actually required for cruising the vehicle, resulting in wasteful fuel consumption and noisy engine operation.
The present invention is proposed by taking the above-mentioned drawbacks into consideration.